For a sedan, one sub, 300 W. It’s the same math as the designer’s step-by-step mode, where you can fit the box to your space, vehicle and amp and get plans, a cut sheet and DXF.
Sealed Ported · SPL in dB at 1 W / 1 m, no cabin gain
Thiele/Small parameters
Fs
37 Hz
Qts
0.24
Qes
0.25
Qms
7.11
Vas
1.38 ft³
Re (one coil)
1.4 Ω
Sd
125.6 in²
Xmax
1.34″
Vd
168.1 in³ calc.
Mms
440 g calc.
BL
23.9 T·m calc.
EBP
148 — suits ported calc.
Sensitivity, 1 W / 1 m
91 dB calc.
General
Size
15″
Voice coils
dual 2 Ω
RMS power
—
Mounting dimensions
Cutout diameter
14 1/8″
Mounting depth
11 1/2″
Overall diameter
15 5/8″
“≈” means the value isn’t in the spec sheet and a typical value for the size is used; “calc.” means it’s calculated from the published parameters. Check the manufacturer’s spec sheet before you build.